Al-Qaeda in Iraq returned after a period of lull to use Syrian soil to smuggle fighters into Iraq, The Washington Post reported. It hinted that the resumption of this activity was part of President Barack Obama administration's consideration to continue sanctions on Syria.

The former administration has slammed Syria for the transit of foreign fighters, suggesting that the regime in Damascus was involved in the traffic, the report said. "We do think that the knowledge of these networks exists at least within the Syrian intelligence community," the paper quoted an unnamed senior US military official as saying. "What level, if it's low or high up, we just don't have a good gauge on."

According to the report, General David Petraeus, who heads the US Central Command, told Congress in April that the Al-Qaeda in Iraq pipeline through Syria had been "reactivated."